Remote Weather Sensors

We are looking at using the Arduino to test a project that involves sending some weather/positioning data wirelessly (likely over Bluetooth) for use in another project. I’m not so concerned about the wireless data transmission as I am the data themselves.

We are looking to find some inexpensive sensors with fairly high accuracy/frequency/response time to be placed on vehicles around severe thunderstorms and the data to be collected against video from another source.

I did a search on Arduino temperature sensors as a start as was overwhelmed with what’s out there.
Ideally we’d like to measure:
Outside air temperature (accuracy maximized in typical ranges of -40 to 120F), outside dewpoint, outside humidity (0-100%), outside pressure (will be later corrected to sea level standard via post-processed), and GPS (lat/lon/elevation).

We’d like sensors that are as accurate as possible, can be sampled at least 1 Hz (1 observation per second), and have very fast response due to the rapidly changing conditions. Unlike the storm chase vehicles you may be familiar with sporting large PVC pipes, etc…on their roof tops, we are looking for a very small footprint with the Arduino, BT shield, weather and GPS sensors all fiitting within a very small louvered box (for airflow) that can be mag-mounted along with a battery pack. Ideally the sensors should use very low wattage so the whole thing can be powered off some rechargeable batteries.

Bottom line, has anyone done some research grade type work with temperature, humidity, etc… sensors that can recommend a couple companies that provide some decent quality stuff on the cheap that is easy testable with a basic Arduino?

Thanks in advance!
Evan

I'd consider the DHT22 series of RH and temp sensors. Inexpensive ($10), uses a digital bus (so less sensitive to noise), and I hope the accuracy is good enough. There is a Arduino library for the DHT22, so interfacing with the thing is super easy. Sparkfun also sells barometric pressure sensors. Another great place for sensors and good advice /tutorials is adafruit.com.

Modern Device sells a solid-state wind-speed device that folk have successfully used. I use a simple in-speed cup unit that works great (hall effect sensor).

I have never worked with GPS sensors, can't help you there, sorry!

Instead of communicating via bluetooth, another approach worth thinking about is a real time clock like the Chronodot and a small SDHC or other flash device to write to. Time stamp each entry and you're good to go, with minimal chance of interference.

Think about the enclosure you're housing them in - otherwise irradiance may influence your measurements unduly.

A very very useful and well thought out reply! Keep 'em coming.

For humidity the DHT is a nice sensor. DHT library - http://arduino.cc/playground/Main/DHTLib - supports both DHT11 and DHT22 (go for the 22 if you want more precission). The DHT series can only be sampled at 0.5 Hz (2 seconds between readings) but humidity does not change that fast in general.

A dewpoint function can be found here - http://arduino.cc/playground/Main/DHT11Lib -

For temperature I like the DS18B20 (digital sensor) and since a few weeks the LM34 (analog sensor that does Fahrenheit, LM35 its sister does Celsius :)

Can you tell something about the precission and accuracy you want to achieve?

Ciao,

if You need a sensor with more accuracy you can also use IST and Sensirion sensors.

IST use I2C protocol for humidity-temperature sensors. http://www.ist-ag.com/eh/ist-ag/en/home.nsf/contentview/~humidity-modules

IST uses a protocol called ZicWirethat is like 1-Wire for temperature sensors. Accuracy down to +- 0.1 °C. http://www.ist-ag.com/eh/ist-ag/en/home.nsf/contentview/F6D7CEE18FC82919C125789400182A81

Sensirion uses his own protocol or I2C http://www.sensirion.com/en/01_humidity_sensors/00_humidity_sensors.htm

For both You can find Arduino libraries. Ciao, Marco.